Skip to main content

Breaking down
RTC security

A blog about vulnerabilities and attacks affecting VoIP and WebRTC applications and infrastructure by Enable Security.

Read our newsletter
a phone receiver being crushed by a hand
Sandro Gauci

Sandro Gauci, Enable Security

RTCSec newsletter is one year old!

Published on Oct 26, 2022

Roughly a year ago, we sent out the first RTCSec newsletter and have been doing so every month. Each time, we have covered more and more of our favourite topics, VoIP and WebRTC security. And now, it has become our primary way of keep up to date with what is happening, and our most regular publication too. If you are not yet subscribed, do so at https://rtcsec.com/subscribe. The next one is out in a few days!…

Read more »

SIPVicious PRO experimental now supports STIR/SHAKEN and 5 new tools

We just made two builds available to our SIPVicious PRO members. One is called the stable build, while the other is the experimental build. The v6.0.0-beta.5 stable build includes a large number of fixes, much better (or sane) defaults and full coverage of SRTP throughout the toolset. The experimental version is where the excitement is. Our members now have access to 5 new tools that we find useful in our work:…

Read more »

Ali Norouzi

, Sandro Gauci

Sandro Gauci, Enable Security

Kamailio’s exec module considered harmful

Last updated on Jan 26, 2023 in ,

Executive summary (TL;DR) The combination of pseudo-variables and Kamailio’s exec can be risky and may result in code injection. By using special SIP headers and environment variables, it becomes effortless to exploit a vulnerable configuration. We have created a Docker environment to assist readers in reproducing this vulnerability and testing solutions. Protection is tricky and the official documentation may have previously misled developers - we aim to fix that by updating the module’s official documentation.…

Read more »
Sandro Gauci

Sandro Gauci, Enable Security

How to perform a DDoS attack simulation

Last updated on Nov 29, 2022

TL;DR A DDoS simulation is a practical exercise that various organisations are capable of doing. Understand the reasons why you would want to do this, then combine custom with off-the-shelf attack tools. Follow the best practices, apply solutions and mitigation; and you can finally answer: what if we got attacked? Introduction In this post, we give an overview of how you too can perform your own distributed denial of service (DDoS) simulation exercises.…

Read more »
Sandro Gauci

Sandro Gauci, Enable Security

Exploiting CVE-2022-0778, a bug in OpenSSL vis-à-vis WebRTC platforms

Executive summary (TL;DR) Exploiting CVE-2022-0778 in a WebRTC context requires that you get a few things right first. But once that is sorted, DoS (in RTC) is the new RCE! How I got social engineered into looking at CVE-2022-0778 A few days ago, Philipp Hancke, self-proclaimed purveyor of the dark side of WebRTC, messaged me privately with a very simple question: “are you offering a DTLS scanner by chance?” He explained how in the context of WebRTC it would be a bit difficult since you need to get signaling right, ICE (that dance with STUN and other funny things) and finally, you get to do your DTLS scans.…

Read more »
Sandro Gauci

Sandro Gauci, Enable Security

Killing bugs … one vulnerability report at a time

Executive summary (TL;DR) We tell the story behind the latest FreeSWITCH advisories and how it all came together one sleepless night in April 2021 so that we ended up with 4 vulnerabilities that needed reporting. And then, one more vulnerability found due to a bug in our own software, SIPVicious PRO. We explain how these flaws were discovered, reported, fixed and what we ultimately learned through this process. What is this about?…

Read more »

Ali Norouzi

, Sandro Gauci

Sandro Gauci, Enable Security

Kamailio’s exec module considered harmful

Last updated on Jan 26, 2023 in ,

Executive summary (TL;DR) The combination of pseudo-variables and Kamailio’s exec can be risky and may result in code injection. By using special SIP headers and environment variables, it becomes effortless to exploit a vulnerable configuration. We have created a Docker environment to assist readers in reproducing this vulnerability and testing solutions. Protection is tricky and the official documentation may have previously misled developers - we aim to fix that by updating the module’s official documentation.…

Read more »

Abusing SIP for Cross-Site Scripting? Most definitely!

Last updated on Jun 10, 2021 in , ,

Executive summary (TL;DR) SIP can be used as an attack vector for AppSec vulnerabilities such as cross-site scripting (XSS), potentially leading to unauthenticated remote compromise of critical systems. VoIPmonitor GUI had one such vulnerability which highlights this attack vector exceptionally well. The following writeup explores how persistent backdoor administrative access can be obtained by sending malicious SIP messages. This vulnerability was reported by Enable Security and fixed in VoIPmonitor GUI back in February 2021, using standard cross-site scripting protection mechanisms.…

Read more »

Attacking a real VoIP System with SIPVicious OSS

Last updated on Jun 8, 2020 in , ,

Recently, we put out a target server on the Internet at demo.sipvicious.pro which hosts a Kamailio Server handling SIP over UDP, TCP, TLS as well as WebSockets. Behind that, the observant reader will soon discover that an Asterisk server handles the voicemail and echo services. This is actually a fully functioning (real) VoIP system that’s ready to be attacked. Therefore, in combination, these software packages allow us to reproduce a number of common security vulnerabilities affecting VoIP and WebRTC systems.…

Read more »
Sandro Gauci

Sandro Gauci, Enable Security

Jitsi Meet on Docker default passwords - how bad is it, how to detect and fix it

Last updated on Apr 20, 2020 in , , , ,

Executive summary (TL;DR) Jitsi Meet on Docker contained default passwords for important users, which could be abused to run administrative XMPP commands, including shutting down the server, changing the administrative password and loading Prosody modules. We also provide instructions on how to check for this issue if you administer a Jitsi Meet server. Background story A few days ago we noticed a tweet by @joernchen mentioning something that sounded familiar, Jitsi.…

Read more »